Part 6

That a scientific theory is, in some sense, a personal achievement, becomes evident when we study a number of theories lying within the same branch of science. The ordinary belief that science is completely impersonal is certainly not true. And yet it is not easy to see how a scientific theory can express the personality of its author; it is difficult, that is to say, to understand in what way a scientific theory can resemble a work of art. It seems that the fact that a scientific theory must have “objective truth” renders it an altogether different thing from a work of art. It would be more just to say that the element of objective truth radically differentiates a scientific theory from those works of art which are independent of all experience of life--as certain musical compositions may be, for instance. But it is not clear that, in general, works of art are independent of objective truth; all those works of art which assume experience claim assent--they do, in their intention, claim universal assent--to the truth of their assumptions. The serious artist believes his personal vision to be true; he will not, probably, claim “absolute” truth for it, but neither does a scientific theory profess to be absolutely true. And, further, works of art and scientific theories exist to serve the same purpose--to aid comprehension. An artist’s chief title to consideration is to be found in the depth and extent of his vision, in the profundity and range, that is to say, of the comprehension he makes possible. The value of a scientific theory is judged by the same criteria. So far, therefore, it would appear that the chief difference between a work of art and a scientific theory is to be found in their subject-matter. It cannot even be said that the subject-matter is arranged to serve different ends in the two cases, for in each case the end which is aimed at is æsthetic satisfaction. Comprehension is one of the elements of what is loosely termed the æsthetic emotion, and it is the most important element. Even when we descend to particulars, and study the quality of similes in poetry, and, indeed, “ornamentation” generally, we shall find the criterion we employ is still the degree of comprehension afforded by the device. But we cannot here work out the analogy in detail. It is sufficient to show that works of art that have a reference to experience, to an external world, in short, are, in important respects, similar to scientific theories.

Since, then, a work of art, although conditioned by experience, may nevertheless be a personal achievement, we need have no a priori objection to conceding personality to a scientific theory. In each case it is the method of transformation from what we may call the raw material to the finished product which is the personal thing. The artist’s raw material, whether it be the Thames in a fog, a number of incidents from Holinshed, or the lives of the inhabitants of a Russian village, is no more and no less common property than are the données from which a scientific man constructs a theory; the end product, also, in each case, claims universal assent and bestows comprehension. What is personal is the law of transformation by which the one objective thing is changed into the other objective thing. The law of transformation is different for each individual mind, and this is as true of scientific men as of any other sort of men. In this sense, then, both works of art and scientific theories are personal achievements. A history of science written from this point of view would be instructive. It would be interesting to trace the personal element in each great scientific achievement, to show what kinds of personalities have dominated us, to see what meaning eccentricity can have as applied to the thought of a scientific man. But although a detailed history of this kind has not yet been written, certain national differences have long been recognised.

There is almost as marked a difference between English and French science as between English and French literature. The English scientific mind is, on the whole, intuitive, mobile, illogical, and very prone to imagery of a curiously practical kind. The French scientific mind, on the other hand, likes to simplify the complicated reality to as few terms as possible, and then to build up an impeccable logical edifice. Maxwell was a very fine type of the great English man of science, but we have Poincaré’s authority for saying that the great Treatise on Electricity and Magnetism awakens in the French reader feelings of distrust. So far from finding an impeccable logical structure, he finds that different parts of the book are written from different points of view, and that these points of view are even irreconcilable with one another. Maxwell’s liking for immensely complicated mechanical models, designed to illustrate some abstruse equation, is also a stumbling-block to the French reader. What are such models supposed to prove? Surely Maxwell did not suppose that the æther contained trains of geared wheels with “idle wheels” in between? What mysterious satisfaction did he derive from such unnecessary and irrelevant pictures? But this curious liking for models is characteristic of the English school, and it is a characteristic that Continental physicists have never been able to understand. It is doubtless a manifestation of the English reluctance to get out of touch with experience. The English man of science trusts logic much less than he trusts experience. The Frenchman has much less respect for experience. He is willing to simplify in a way which, to the English mind, is almost outrageous--to see the Universe as a collection of little billiard balls with forces varying inversely as the square of the distance. And on such assumptions he is willing to proceed as far as logic can take him. There is, indeed, a school in France which asserts that all we can ever know of the Universe is its equations; we can never know what they “mean” in the English sense. From the æsthetic point of view there is no doubt that the French method is to be preferred. We can all share Lagrange’s satisfaction when he says, in the Avertissement to his Mécanique Analytique: “Je me suis proposé de réduire la théorie de cette Science, et l’art de résoudre les problèmes qui s’y rapportent, à des formules générales, dont le simple développement donne toutes les équations nécessaires pour la solution de chaque problème.” But we must remember that when the interest is chiefly in the “développement” the assumptions may remain uncriticised. The English way is to hold the assumptions tentatively, and to be always open to the suggestions of experience. The German way, which, if we are to judge by the work of Riemann and Einstein, seems to be to concentrate an immense critical apparatus on the assumptions, is equally interesting. The “philosophic” tendency which is supposed to characterise German thought in other departments, is certainly apparent in its science. The three tendencies are sufficiently marked to constitute national differences and suggest that a detailed analysis of individual achievements would yield equally interesting results.

THE IDEAL SCIENTIFIC MAN

Is the scientific man really a distinct kind of man, or is it merely that science is a distinct occupation? To answer the question we must make the elementary distinction between the scientific man and the man who practises science, and when we do that the answer is obvious. There is as certainly the “born” scientific man as there is the born artist. But in saying this we are referring to ideals. Perhaps there has never been a perfect man of science, and perhaps there has never been a perfect artist. But in order to understand the distinction between one kind of man and another it is helpful to construct ideals--extreme cases which may be used as measuring rods. What, then, are the characteristics of the ideal man of science? We may approach the solution by trying to make precise the characteristics which have led us, vaguely, to construct the hierarchy we already possess. We feel, for instance, that Henry Cavendish, that passionless recluse, was a much more “purely scientific” man than, say, Thomas Henry Huxley. If we examine this conviction of ours we make the interesting discovery that it is chiefly for his negative characteristics that we assign this greater purity to Cavendish. Huxley was passionately interested in the questions which concern every good citizen, in politics, in social reform, in religion; he took sides on these questions and fought for his side. Of Cavendish we can only say that it is inconceivable that he would have taken sides on these questions, and very difficult to believe that he was even remotely interested in them. Take another point. Huxley abounded in ordinary human affections. He was a devoted husband, a good father, a faithful friend, a resolute opponent. Cavendish never manifested a vestige of any of these qualities. He had no wife, no children, no friends, and never showed the faintest dislike of anybody. Huxley was a champion of what he thought the truth, and strained every nerve to enable it to prevail. Cavendish, who was one of the greatest investigators, one of the clearest and most subtle minds, in the history of science, kept his discoveries to himself. For years Huxley bore the brunt of the attacks on Darwin’s theory. Cavendish blandly watched the growth in popularity of theories he had privately demonstrated to be wrong, and never stirred a finger to rebut them. And finally, Huxley was a man who suffered his alternations of high spirits and despondency, hope and despair, while Cavendish, from the evidence we have, was imperturbably serene.

Now, the interesting point that emerges from this comparison is that Cavendish, in virtue of his scientific purity, could not have exhibited those qualities which allied Huxley to the ordinary run of men. A man’s characteristics are not disconnected. Cavendish’s cold passion for knowledge required for its gratification qualities of the spirit as well as of the mind. No man was ever more single in his desire to know; no man ever was so little hindered by having other interests to serve; no man, therefore, had a greater measure of the purely scientific spirit. This is the important point for our question; it is comparatively irrelevant that very few men have ever had so great a mind to place at the service of their passion. That his actual scientific standing should be so much greater than Huxley’s is an accident; he would still have been more purely scientific than Huxley had his ability been less than Huxley’s. Cavendish is all of a piece. His very perfection as a recording and measuring instrument tended to deprive him of “personality.” The less personal he was, in fact, the more dispassionately open he could be. Other passions were incompatible with his perfection; they would derange this exquisite instrument. Judgments of good and evil would not have been natural to him. His reaction to anything was exhausted in the act of understanding that thing.

So far as we have gone, it would seem that Nietzsche’s description of what he calls the “objective man” is exactly what we mean by the ideal man of science. “The objective man is in truth a mirror: accustomed to prostration before everything that wants to be known, with such desires only as knowing or ‘reflecting’ implies ...” he will regard such personality as he has, Nietzsche goes on to say, as accidental and arbitrary. He cannot take himself seriously and devote time to himself. His love is constrained, his hate artificial. He is only genuine so far as he can be objective; he is unable to say either “Yea” or “Nay” to life; he is concerned solely to understand, to “reflect.” He says, with Leibniz: “Je ne méprise presque rien.” This description is undoubtedly the result of genuine psychological insight. When we try to disentangle the purely scientific element in a man of science we find that, so far as he is scientific, he approximates to Nietzsche’s objective man. If this, then, is the ideal scientific man, what place does he occupy? Where does he stand in relation to the rest of mankind? According to Nietzsche he is merely an instrument; “he is an instrument, something of a slave, though certainly the sublimest sort of slave, but nothing in himself.” He is no goal, no termination, no complementary man in whom the rest of creation justifies itself. As compared with the true philosopher, the philosopher in Nietzsche’s sense, the man who gives a new direction to life, the ideal man of science is merely the most costly, the most easily tarnished, the most exquisite of instruments.

We need not quarrel with this valuation, but we would point out that there is an omission in it. The scientific man is an instrument, but he is an indispensable instrument. The human race has endured all the different “new directions” given to it by the “true” philosophers of the past without any marked increase in its spiritual stature. The philosopher, however commanding, who would really lead us in any but a circular direction must have knowledge. This knowledge, to be valuable, must be clear and trustworthy; it must be scientific. And if the inspirations and impulses of our leaders should prove to be incompatible with deductions from scientific knowledge, then we may be sure that the Promised Land does not lie their way. The scientific man is merely an instrument. But it is this instrument alone that can show to mankind which, of all the goals it desires, are possible goals, and which, of all the leaders it trusts, are trustworthy leaders. The scientific man is an instrument, but it is by this instrument that those who would use it are first tested. Scientific knowledge is, if you like, as dispassionate and inhuman as is the universe with which it concerns itself--and it can as little be ignored.

PARALLEL STRAIGHT LINES

Geometry, it has been satisfactorily shown, had a purely empirical origin. It appears that the earliest geometrical formulæ which have been discovered belong to ancient Egypt, and that all these formulæ served a useful purpose. The oldest of them are concerned with the measurements of areas, a class of problem which the yearly sinking of the Nile rendered of great importance. The formulæ obtained by the ancient Egyptians were usually wrong, although they were approximately correct; they evidently rested on no theoretical basis, but were compendious statements of the results of somewhat rough measurements, a point of view which is borne out by the fact that no proof, nor even an attempt at a proof, is anywhere hinted at. So far as the evidence goes, it seems to be established that geometry, as consisting of logical deductions from stated premises, began with the Greeks. A number of theorems of a fair degree of complexity had been developed before they were reduced to a system; before, that is, the assumptions on which they were based were made explicit. The task of discovering the necessary and sufficient assumptions on which a system of geometry rests is one of the greatest difficulty; the necessary combination of subtlety and rigour is rare. The great systematisation of Greek geometry was effected, of course, by Euclid, and although his reduction of the system to its essential assumptions was not final, his performance was such as to awaken the admiration of great mathematicians in every succeeding century. But there is one point in which this great reduction is notably imperfect--the so-called parallel axiom. It says, essentially, that through a given point only one line can be drawn parallel to a given straight line. It was felt, even by the earliest commentators on Euclid, that this postulate did not possess quite the same degree of self-evidence as was manifested by the others. It was necessary, they felt, to give a proof of this postulate; they attempted to improve on Euclid’s work in a number of minor ways, but it was the parallel axiom which they were most concerned to revise; the proof of this postulate should be contained, they thought, in the other postulates. The attempts to supply this proof were all fruitless, and the sixth century was reached with this nine-hundred-years-old disfigurement still persisting. For some time after the sixth century the world rested from Euclid’s parallel axiom; indeed, it rested from geometry altogether, and the old empirical outlook of the Egyptians, and even their formulæ, again became current. But the Greek culture penetrated to the Arabs, and with the Greek culture came the riddle of Euclid’s axiom. Again proofs were attempted; a famous attempt is that of Nasir Eddin, who flourished in the thirteenth century. In 1663 John Wallis made the important discovery that unless the parallel axiom be assumed, similar figures of different sizes are not possible, that is to say, that if we are to assume that shape is independent of size, then we must assume Euclid’s parallel axiom. Many of these attempts brought out points of interest, but none of them were successful. In the year 1733, however, the whole research took on a new complexion with the publication of Girolamo Saccheri’s Euclides ab omni naevo vindicatus. The importance of this work consists in the fact that, although it was written to vindicate Euclid’s parallel axiom once for all, it contains the first real outline of a non-Euclidean geometry.

Saccheri was a Jesuit, and it was in 1690, while he was teaching grammar in Milan, that he first studied the Elements of Euclid. He was a man of very great acumen, and when he, in turn, succumbed to the spell of the parallel postulate, he brought to bear on it a more subtle and rigorous logic than had yet been applied to it. Thirty-six years before he published his treatise on Euclid he had published a book on logic which gives him a high place as a logician. In it he is particularly concerned with investigating the compatibility of different assumptions or postulates. His method was to determine whether a member of a group of postulates is independent of the others by finding a particular case in which the postulate in question is not true while all the others remain true. If such a case can be found, it is obvious that the postulate in question cannot be deduced from the others, else it would be true whenever they were true. This was the method he applied to the parallel postulate of Euclid. He showed that the parallel postulate is equivalent to saying that the three interior angles of a triangle are equal to two right angles. He proceeds, therefore, in accordance with his method, to develop the consequences of supposing them less than, or greater than, two right angles. In the latter case he succeeds in showing that we are led to impossible conclusions, since he assumed, as everybody assumed for more than a century after, that the straight line is of infinite length. But in the former case, the hypothesis that the interior angles of a triangle are together less than two right angles, Saccheri, although he struggled very hard, did not succeed in falling into contradictions. He does not seem to have had the boldness necessary completely to trust his own logic, but the fact remains that, accepting the rest of Euclid’s axioms and denying the parallel axiom, he developed a logically consistent geometry.

There is reason to suppose that Saccheri’s work had some influence on subsequent thought, although its full significance was certainly not perceived. The parallel axiom continued to be investigated, and the total effect of all these efforts was to induce a doubt concerning the absolute necessity of the Euclidean geometry. Such a doubt was very daring; for two thousand years the postulates of Euclid had been accepted as absolutely true; the fact of their existence had profoundly influenced philosophy, and, indeed, theology. But the doubt persisted and grew, until finally, early in the nineteenth century, a perfectly logical and consistent non-Euclidean geometry, one explicitly denying the parallel postulate, was published to the world. As so often happens, the great step was taken by two men independently of one another, Lobatschewski, a Russian, and Bolyai, a Hungarian. It appeared, however, that both had been preceded by that great mathematical genius, Gauss, although he had been too timid to publish his conclusions. The new geometry developed the consequences of that one of Saccheri’s alternatives which supposed the interior angles of a triangle to be less than two right angles. The whole outlook on geometry now assumed a new complexion. Riemann tried the effect of denying the infinity of the straight line and of developing Saccheri’s other alternative. He found he was led to no contradictions. But with Riemann’s work we come to a yet further extension of geometry--the extension to space of four, five, or any number of dimensions. And these investigations, which seemed for some time to constitute the most gratuitous, although the most profound and subtle, exercises of the mind, have now received their complete justification by flowering into the Generalised Principle of Relativity.

THE NEW SCIENTIFIC HORIZON

About current scientific speculations there is one characteristic, subtle, perhaps, but profound and far-reaching, which distinguishes them from the scientific speculations of the Victorian age. We can best isolate this characteristic by considering it as a particular manifestation of something which is met with in nearly every phase of contemporary life--something which may fairly be called the Zeitgeist of our time. This spirit is chiefly a sense of unlimited possibilities, a sense that the radically new and unprecedented may be upon us; with this feeling comes a recrudescence of the spirit of adventure; there are unknown paths leading to vague but--probably--splendid goals. In the Victorian age the main lines of everything were settled; the chief features of the universe were known. There were matter and energy, and there was, of course, the æther. The astronomical and geological scales were known in broad outline, and a first survey of the march from amœba to man had been taken. The work of future ages was to fill in the details. The universe of the Victorians was a large and rather grand affair, but it was sombre. Those emotional barometers, the poets, in so far as they were aware of the scientific outlook, either “transcended” it or were crushed by it. Jules Laforge furnishes an excellent example of the effect of the Victorian scientific outlook on an intelligent and sensitive mind. His reaction was to compose funereal dirges on the death of the earth and the extinction of mankind. The universe of the Victorians was objective, indifferent, tracing a purposeless pattern in obedience to “iron” laws. It was a universe which held no great surprises.

It is obvious that a very different spirit is abroad to-day. At the present time the general consciousness seems to hold that almost anything is possible. In part this may be accounted for, as in other ages, by credulity based on ignorance, but there is also a credulity based on knowledge, and it is this aspect of the general attitude which deserves attention. The two kinds of credulity may be observed in different believers of the same statements. Spiritualism, for instance, has its followers amongst those who are unfamiliar with investigations in the subject and amongst those whose belief has been compelled by their very knowledge of the investigations. And disbelievers form two exactly similar classes. There is also a credulity--the most common kind--based on neither ignorance nor knowledge, but on partial knowledge. Thus knowledge, but incomplete knowledge, of such phenomena as wireless telegraphy or telephony, seems to predispose many people to believe “wonders” which have no real connection with those phenomena, but which are merely as inexplicable by partial knowledge. Undoubtedly the recent developments in science are responsible for much of this kind of credulity. But the new indulgence of possibilities, as exhibited by the man of science, is dependent on quite different considerations. To the student of physics, at any rate, the work of the last two or three decades has been peculiarly disturbing. He has been called upon, not merely to revise and extend his knowledge, but to alter his assumptions. It is in this respect that the physics of our own day chiefly differs from Victorian physics.

The distinctively modern epoch began with the promulgation of the Electron Theory. That “matter” could be “electrified” was easily granted. The fact that the famous question, What is electricity? could not be answered was no difficulty in admitting the fact that, as a result of certain processes, matter could be made to exhibit certain phenomena which could conveniently be referred to the fact that it possessed an “electric charge.” And the discovery of particles very much smaller than a hydrogen atom presented no conceptual difficulties. The fact that the ultimate particles of matter were smaller than had been supposed could easily be granted; the new assumption was of the same kind as the old one. And, further, to admit that each of these particles possessed an electric charge made no unfamiliar demands on the imagination. But the next step, that these particles consisted of nothing but an electric charge--that was a very different thing. The early popularisations of the idea show something of the mental confusion it caused. “Disembodied charges of electricity” was a favourite descriptive phrase; many physicists fought hard to retain even a nucleus of “ordinary matter” on which this charge could be supposed to be lodged. That an electric charge could exist apart from matter seemed to many people as difficult to conceive as motion without anything which moved. But the conception speedily became familiar; that useful entity, the æther, soon made things easier. For the disembodied charge, the electron, could be conceived as a local distortion of some kind in the æther, and, by endowing the æther with some sort of substantiality, the hypothesis that matter was in some way built up out of this primitive substance could be tolerated. But the general effect of the theory was to give a more philosophical tinge to science. The gross, easy assumptions of everyday thinking about “matter” had to be revised; articles were written showing that matter was really immaterial, and materialism was conjectured to have received a severe set-back.

The mind had barely become accustomed to the new assumptions before it was again profoundly disturbed by the publication of Planck’s Quantum Theory. The theory, which was invented to explain certain radiation phenomena, asserted, briefly, that energy was atomic. One’s most intimate assumptions were disturbed. Men of science are not usually accustomed to philosophic exercises, and the idea that energy, which they regarded as necessarily continuous, had an atomic structure seemed at first almost meaningless. If we consider, for instance, the energy possessed by a moving body, it seems natural to suppose that this energy can be increased or diminished in a continuous manner; the idea that its energy can only increase or decrease by finite jumps was a very strange idea, and led again to a scrutiny of assumptions which had appeared fundamental in science. Here, again, objections to the new theory were sometimes the outcome purely of mental inertia, of an inability to examine and discard a way of thinking which seemed almost a necessary consequence of the structure of the mind. The last great bouleversement of one’s fundamental assumptions has been, of course, Einstein’s generalised theory of relativity. Here we are asked to revise our most deep-rooted assumptions--so deep-rooted that we are, for the most part, unconscious of them--our assumptions regarding space and time.

It is this thorough overhauling of primary assumptions which distinguishes the modern progress in physics from all the progress of the Victorian age. Physics has not merely been extended, it has become a radically new thing, and there are very good reasons for supposing that it is going to change still more. A certain sense of unknown possibilities is therefore natural, even if it be the product merely of bewilderment. The total effect of the new ideas is to make the universe of physics less objective; to an unsuspected extent this indifferent universe, with its iron laws, is a product of our own minds. To some extent this fact was always recognised, particularly by the Continental physicists, but as a general persuasion it is comparatively recent. We cannot escape the structure of our own minds, it is true, but we do not yet know what that structure is; we do not know what barriers are breakable; we do not know what thoughts are thinkable by man. A universe in whose construction so plastic and mysterious an entity as the mind of man collaborates, may very well hold great surprises.

THE HOPE OF SCIENCE

It is not an unfair judgment, we think, that decides, on a survey of contemporary intellectual activities, to grant science the first place. Whether we consider the quality of the work which is being done, its importance to mankind, or the spirit in which the work is done, we think science earns that place. Our age is a scientific age to an extent which is certainly not generally realised. Contemporary scientific work is of a quality fully comparable with that of the greatest periods of its history; it is inevitable that our age should emerge, in the history of the future, as an age of science. It has, indeed, already established a perspective which leads to a revaluation of the Victorian age. There have already been many writers who have thought that age more memorable for its science than for its other achievements, that its significance to humanity lay more in the work of Darwin, Faraday, and Maxwell than in that of Tennyson and Matthew Arnold, or even in that of Mr. Gladstone, but the perspective we have now obtained puts the matter almost beyond doubt. With most of us our outlook is the result of a decrepit tradition. Our orientation towards life, so far as we are conscious of having one, is based upon the values we attribute to the various objects of our thoughts, and these values are determined partly by our instinctive desires and partly by the suggestions of our education--using the term “education” to include all converse with the minds of our fellows. Education, so defined, is the result very largely of a long and widespread tradition, a general tradition of European culture. It is a curious fact that, although the history of science goes as far back as the history of the arts, science is not an integral part of this, nevertheless, very catholic culture. There are periods, it is true, when some scientific theory is sufficiently dramatic, or appears sufficiently pertinent to man’s destiny, to secure general attention; Newton’s theory of gravitation, Darwin’s theory of evolution, and Einstein’s theory of relativity have each given rise to such a period. Einstein’s theory, we are informed, is now the favourite topic of enlightened conversation in Parisian salons, as Newton’s theory once was. Some of this interest, no doubt, is the product of disinterested curiosity, and in that respect is vastly different from the once general interest in Darwin’s theory. But we fear that many of those who are curious about Einstein’s theory would, if they understood it, find it uninteresting. We dare not interpret this curiosity as a sign that people are beginning to be as naturally interested in science as they are in literature, for instance.

Nevertheless, we believe that the old culture is moribund in the sense that its particular scale of values is undergoing revision. Science is becoming less an affair for specialists; it is acquiring a “human” value. An increasing number of people are beginning to realise that a great science, such as Physics, may offer objects for contemplation which are as delicate, as subtle, as exquisitely harmonious as the dreams of Plato--and much better founded. And in relation to man, his present state and possible future, science alone, to those who are not satisfied with less than verifiable knowledge, speaks with the accent of authority. The great constructions of science are grandiose without being chimerical; they are beautiful but not deceiving. Indeed, one sometimes has the feeling that it is only in science, nowadays, that one still meets with the spirit of adventure, the sense of boundless and glorious possibilities, with an exultant hope. Our poets and men of letters generally are extraordinarily tame and disillusioned creatures compared with our romantic and daring men of science. It is refreshing to turn from the lamentations of our literary men to such a book as the Space, Time, Matter of Hermann Weyl, if only for the fervour, the immense enthusiasm with which that highly accomplished mathematician writes. Einstein is his Columbus, with the difference that his America has indicated the existence of yet vaster continents. And this enthusiasm is justified by its fruits; it has inspired Herr Weyl to make what is unquestionably the greatest advance on Einstein’s own work which has yet been made. It is not in Physics alone that we find this note. To the biologists, also, the world has become young again. Should our ignorant and unimaginative politicians, and our still more ignorant and unimaginative business men, succeed in turning the whole heroic effort and age-long struggle which has produced our present culture to a mockery, they will put an end to a curiously interesting and promising transition age, to an age which is at once fin de siècle and at the morning of a glorious renaissance. But if they do not succeed, if the ordinary man shows himself even a little worthy of the immense travail of his species, then we prophesy that science will become an integral part of the culture of the future. The new physics, the new biology, the new psychology, will be too obviously pertinent to all man’s chief preoccupations for us to be able to pretend that the present narrowly conceived humaniora furnish a liberal education. We even believe that if the old arts are to become youthful again, it must be by a transfusion of blood. It will not be sufficient that the philosophy and literature of the future should “accommodate” themselves to the scientific outlook; they must be inspired by it.

Meanwhile, scientific men must be charitable; they must believe the best. If science is to become an integral part of culture, scientific men must help to make this possible. We believe that much of the present interest in science is genuine; that it springs from a serious attempt on the part of many people to find out what science can tell them about themselves and the Universe they live in. Science is not hunted purely for its dividend-earning capacities or for its power of providing new thrills. Einstein, we understand, is suspicious of the popular interest his theory has evoked; “a mere fashion,” he says. And doubtless his suspicion is largely justified. But we believe there is more in it than that--that there are many who, besides valuing the delightful dreams of the poets and philosophers, have an affection for knowledge. And when they find that the constructions of science are not one whit less delightful than the dreams of the poets, this affection may give rise to a permanent attachment. And with these new objects of interest will come a change in values. Men will learn to differentiate in their beliefs between those which are mere indulgences of emotion and those which correspond to objective truth. This is the path by which the mind becomes mature. It may not be, in all stages, a pleasant process, but it leads to increased freedom and increased power. The impossible will no longer be attempted, but the region of the possible will be seen to be vastly greater. Man will see in what directions he can shape his destiny, and he will be able to enter on the task with a rational hope. All his courage and endurance will have a chance of victorious achievement; he will know that he is not engaged in a forlorn hope; the world will become young again.

THE RETURN OF MYSTERY

“It is a universal condition of the enjoyable that the mind must believe in the existence of a law and yet have a mystery to move about in.”--JAMES CLERK MAXWELL.

That our thinking, and with it our feeling, is largely conditioned by assumptions which have no logical necessity, is a commonplace of philosophy, and is indeed apparent to the slightest introspection. Characteristic of any age is a body of beliefs, resting on more or less good evidence, and a group of feelings associated with those beliefs. The German language, so rich in indefinite but valuable general terms, afforded the word Zeitgeist for this complex, a word we have directly translated into the Spirit of the Age. The name is a good one; it indicates that we are dealing with something which is widely diffused and also subject to change. It is subject to change, but it plays a dominating rôle in the age to which it belongs. The Spirit of the Age is something that practically all the intellectual life of the age has in common. It is not manifested only in philosophical treatises or in works of art; it is often manifested even more strikingly in statesmen’s speeches and a country’s domestic and foreign policy. It is a kind of intellectual and emotional atmosphere of which everybody is aware, but which probably nobody could define. We see, however, that a very important part of it consists of a sense of probability, of a tendency to accept certain kinds of explanation and to reject others.

For the last few decades, at any rate, Science has been the chief factor in forming this omnipresent sense of probability. As a matter of fact, it is probable that the influence of Science in forming the Spirit of the Age can be traced a very long way back, as far back as Copernicus. Not that we assert the existence of a close connection between the Science and the other intellectual activities of Copernicus’s own age. The influence of which we speak is likely to manifest itself gradually; in particular, it may take a long time to affect the arts. And by the time it has percolated so far its origin may be forgotten; it may appear as a subconscious rather than as a conscious group of assumptions. By the time a scientific discovery becomes part of the mental furniture of an age, many of what were originally its possible implications will have become an integral part of it. The original discovery will then be merely the nucleus of a rich intellectual and, possibly, emotional complex, of which the parts are no longer envisaged separately. The work of Newton, for example, and the great body of exact investigations he made possible, influenced the outlook of the nineteenth century chiefly in the direction of making determinism plausible. Such lecturers as Tyndall could confidently appeal to this mental predisposition on the part of their audience, although they had no need to postulate any direct acquaintance with the work of Newton and of his successors. The fact that Newton successfully formulated exact laws for the description of natural phenomena is the important aspect of his work from our present point of view. The influence of Copernicus was rather different. From the point of view of the history of Science his importance is that he made Newton possible; from our present point of view his importance is that he made Darwin possible. Copernicus’ destruction of the isolated position of man’s planet in the solar system prepares the mind for Darwin’s destruction of the isolated position of man in the animal kingdom. They each shocked the same set of prepossessions.

The “materialistic philosophy” which was so marked a feature of the latter part of the nineteenth century, and which still forms, we believe, the prevalent intellectual complexion, owed the whole of its plausibility to its supposed scientific backing. Its basis was not merely biological; physics played quite as great a part as biology. The notion of determinism derived its strength, as we have said, chiefly from physics; biology was not in a position to demonstrate the exact correspondences required. The ultimate grandiose vision of the purely natural and inevitable march of evolution from the atoms of the primitive nebula to the British Association for the Advancement of Science, as outlined by Tyndall in his Belfast Address, assumed the results of physics and astronomy as much as Darwin’s Origin of Species. It was because biology was not the only science involved that it was possible to found a “materialistic” philosophy on Darwinism. One primary assumption of that philosophy, that life arises from “dead” matter, not only had no biological support, but had been decisively refuted by the experiments of Pasteur. But, as related to the general movement of Science, the hypothesis had the necessary plausibility. Considering the then existing evidence, this hypothesis, together with the hypothesis that mental states are produced by atomic movements in a strictly determinist manner, are, indeed, striking instances of the way in which the Zeitgeist, as much as the evidence, determines the direction of our thinking.

The importance of such conceptions cannot be over-estimated. Directly or indirectly they influence the whole life, if not of their time, then of an age which succeeds them. The philosophy in question had existed for centuries, of course; what made it influential was the scientific backing it received, for, in these matters, Science has for some time past played the dominant rôle. Neither religion nor philosophy has been able successfully to oppose it; nowadays, indeed, they seem concerned only to agree with it. And if, here and there, a few artists have felt themselves outraged by what were supposed to be the teachings of Science, their influence has not been sufficient to deflect the stream. Such isolated protestants have had nothing but their feelings to oppose to what were considered to be facts, and the world, with what may have been a stupid honesty, has followed after the supposed facts. But the influence of Science on the arts would require a separate investigation. A certain stability is given to some serious art by its own tradition, and this may lessen its sensitiveness regarded merely as an indication of the spirit of its age. It is, nevertheless, very sensitive. In a history of modern literature, for example, it is impossible to exclude direct references to Darwin; it is usual, indeed, to devote some space to such “influences.” And the artist who is not at home in his age may be reduced to impotence by it. Dostoevsky is a magnificent example of a writer who, extremely sensitive to the spirit of his age, and profoundly understanding it, strove to transcend it. A smaller Dostoevsky might well have been nothing. And is a post-Darwinian Beethoven, or a post-Darwinian Dante, really conceivable?